Note: Descriptions are shown in the official language in which they were submitted.
CA 02913772 2015-12-02
RELEASABLE ANCHOR CABLES FOR CABLE BARRIERS THAT RELEASE UPON
CERTAIN LOAD CONDITIONS UPON THE CABLE BARRIER
This application is a divisional of Canadian patent application Serial No.
2,651,237 filed
internationally on May 4, 2007 and entered nationally on November 4, 2008.
TECHNICAL FIELD
The present invention relates to improvements in and relating to cable-
barriers. In
particular, though not solely, the present invention is directed towards an
anchoring
system for cable-barriers, for use in roading networks and/or vehicle road
lanes requiring
separation by a barrier.
BACKGROUND ART
The present invention will now be described in relation to cable-barriers for
use in relation
to roading networks. However, this should not be seen as limiting, as aspects
of the
present invention may also have application in relation to different fields.
Existing cable-barriers which employ a cable assembly as part of the barrier
have a
variety of different ways for anchoring the cable assembly to the ground, at
the terminal
ends of the cable-barrier. Typically, the cable(s) employed in the cable-
barrier are guided
through one or more terminal posts and are inclined towards one or more ground
anchor
points.
However, one problem with existing anchoring systems is that the inclined
nature of the
cable(s) at the terminal end of the barrier, together with the integrity of
the anchoring
system, acts to effectively create a ramp when impacted by an errant vehicle.
As a
result, the impacting vehicle either rolls or becomes at least partially
airborne, following
an impact.
Some existing cable-barriers, such as the cable-barrier system manufactured by
Gibraltar, have attempted to overcome this 'ramping' problem by having their
cables
anchored to the ground via a quick release mechanism.
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However, one draw back of existing cable-barrier systems is that the anchoring
systems
only function in one direction. If a vehicle impacts the cable-barrier in the
other or
'reverse' direction, snagging of the vehicle between the cables can occur,
which in turn
causes substantial damage to the vehicle and potentially more harm to the
driver.
Another drawback of existing cable-barriers is that if hit in the 'reverse'
direction, ramping
of the vehicle may still occur.
In the inventors experience, no such quick release mechanism has been fully
effective at
reducing or preventing an inclined cable anchoring system from acting as a
ramp or
snag, during impacts from a number of different angles, particularly 'reverse'
direction
impacts ¨ these are impacts that occur in a direction other than a
substantially head on
impact.
It would therefore be useful to have a cable-barrier system or release
mechanism that
could withstand impact from collisions from both directions. Additionally, it
would also be
useful to have a cable-barrier which can release the anchor-cable downwardly
extending
from the terminal post of a cable-barrier, in situations where the anchor-
cables are
capable of acting as a ramp or snag during a collision.
It is an object of the present invention to address the foregoing problems or
at least to
provide the public with a useful choice.
No admission is made that any reference constitutes prior art. The discussion
of the
references states what their authors assert, and the applicants reserve the
right to
challenge the accuracy and pertinency of the cited documents. It will be
clearly
understood that, although a number of prior art publications are referred to
herein, this
reference does not constitute an admission that any of these documents form
part of the
common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term 'comprise' may, under varying jurisdictions,
be attributed
with either an exclusive or an inclusive meaning. For the purpose of this
specification,
and unless otherwise noted, the term 'comprise' shall have an inclusive
meaning - i.e.
that it will be taken to mean an inclusion of not only the listed components
it directly
references, but also other non-specified components or elements. This
rationale will also
be used when the term 'comprised' or 'comprising' is used in relation to one
or more
steps in a method or process.
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Further aspects and advantages of the present invention will become apparent
from the
ensuing description which is given by way of example only.
DISCLOSURE OF INVENTION
The term 'cable-barrier or grammatical variations thereof refers to a barrier
that is
constructed from one or more cables and a number of supporting posts.
The term 'terminal post' or grammatical variations thereof refers to the first
post located
at the first distal end of a cable-barrier.
For the purposes of this specification, the term 'anchor-body' or grammatical
variations
thereof refer to a portion of the terminal post which receives and retains one
end of the
anchor cable(s) to the terminal post.
The term 'anchor-cable' or grammatical variations thereof refer to the
cable(s) that
anchor the terminal post and/or the anchor-body to the ground.
The term 'barrier-cable' or grammatical variations thereof refer to the
cable(s) that span
the length of the cable-barrier.
The term 'snag', 'snagging' or other grammatical variations thereof refers to
when a
vehicle impacts the cable-barrier and causes the vehicle to become entangled
between
the anchor-cables and/or barrier-cables.
The term 'ramp' or grammatical variations thereof refer to when a vehicle
impacts a
barrier in a substantially head-on. This impact generally causes the vehicle
to become
airborne.
According to a first aspect of the present invention there is provided an
anchor-body
which includes at least one aperture adapted to, in use:
- receive and retain one or more anchor-cables which are anchored
so as to
counter balance the force applied to the anchor body by one or more barrier-
cable(s); and
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- release said anchor-cables from the aperture during a collision with a
vehicle,
in situations where said anchor-cables are capable of acting as a ramp and/or
snag during said collision.
According to second aspect of the present invention there is provided an
anchor-body for
a terminal post of a cable-barrier;
wherein said anchor-body is adapted to, in use:
- receive and retain one or more anchor-cables which are also anchored to a
.10 support surface so as to counter balance the force applied to the
terminal post
by one or more barrier-cable(s); and
- release said anchor-cables from the anchor-body, during a collision with
a
vehicle, in situations where said anchor-cables are capable of acting as a
ramp and/or snag during said collision.
According to third aspect of the present invention there is provided a
terminal post for a
cable-barrier which includes:
- a cable-portion which has been adapted to, in use, receive and retain one or
more barrier-cables used in the cable-barrier;
characterised in that the post also includes an anchor-body which is adapted
to, in use:
- receive and retain one or more anchor-cables which are anchored so as to
counter balance the force applied to the terminal post by said barrier-
cable(s);
and
- release said anchor-cables, during a collision with a vehicle, in
situations
where said anchor-cables are capable of acting as a ramp and/or snag during
said collision.
According to another aspect of the present invention there is provided an
anchor-body for
a terminal post of a cable-barrier;
wherein said anchor-body is adapted to, in use:
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- receive and retain one or more anchor-cables which are also
anchored to a
support surface so as to counter balance the force applied to the terminal
post
by said barrier-cable(s); and
- release said anchor-cables from the anchor-body, during a collision with
a
vehicle, in situations where said anchor-cables are capable of acting as a
ramp and/or snag during said collision.
The cable-portion may be adapted in a variety of different ways so as to
receive and
retain one or more barrier-cables, when in use.
In general, the cable-portion may be in the form of one or more apertures
through which
the terminal end of a barrier-cable may pass.
In preferred embodiments the cable-portion may be in the form of a slot
through which
the terminal end of one or more barrier-cables may pass.
In further preferred embodiments the cable-portion may be a slot which has a
mouth at
the top end of the post.
The inventor has found an advantage with this embodiment is that any collision
with the
terminal post itself releases the barrier-cables which escape out the mouth of
the slot
when the post deforms. This in turn causes the anchor-cables to be released
from the
anchor-body.
The anchor-body may be adapted to receive and retain and release said anchor
cable in
a variety of different ways.
In general, the anchor-body includes an aperture into which, in use, anchor-
cables may
pass and be retained therein, wherein said aperture is adapted to release said
anchor-
cables upon application of a force.
In some embodiments the aperture may include a frangible portion which will
break off
upon application of a force, so said anchor-cables can exit the anchor-body.
In preferred embodiments, the aperture of the anchor-body, into which, in use,
anchor-
cables may pass and be retained therein, may be in the form of a slot which
includes a
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mouth at one end thereof through which said anchor-cables may exit upon
application of
a force, to release said anchor-cables from the anchor-body.
Preferably, the force applied to the anchor-body, anchor-cables or barrier-
cables may be
applied to the anchor-body in a substantially downward direction with respect
to the
anchor-cables. In other embodiments, the force may be applied to the anchor-
body in a
substantially side-on direction with respect to the anchor-cables. While, in
even further
embodiments, the force applied to the anchor-body may be in a substantially
downward
and side-on direction with respect to the anchor-cables.
In further preferred embodiments the anchor-body may also include at least two
arms
which can extend the anchor-body out from the post. In use the arms position
the
anchor-body on the post so it faces substantially the opposite direction to
the force
applied by the barrier-cables to the post, away from the barrier-cables.
According to another aspect of the present invention there is provided a kit
for erecting a
terminal post for cable-barrier system wherein the kit includes:
- at least one terminal post which includes a cable-portion which
has been
adapted to, in use, receive and retain one or more barrier-cables used in the
cable-barrier; and
- an anchor-body which forms part of the terminal post, or which
can be
attached to said terminal post;
wherein said anchor-body is adapted to, in use:
- receive and retain one or more anchor-cables which are anchored
so as to
counter balance the force applied to the terminal post by said barrier-
cable(s);
and
release said anchor-cables, during a collision with a vehicle, in situations
where
said anchor-cables are capable of acting as a ramp and/or snag during said
collision.
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According to another aspect of the present invention there is provided a cable-
barrier
system which includes:
at least one terminal post, as substantially described above, which
includes a cable-portion which has been adapted to, in use, receive and
retain one or more barrier-cables used in the cable-barrier; and
an anchor-body, as substantially described above, which forms part of the
terminal post, or which can be attached to said terminal post;
wherein the cable-barrier system further includes;
a plurality of posts capable of receiving and retaining at least one cable
therein;
one or more barrier-cables retained within the posts.
According to another aspect of the present invention there is provided a
method of
anchoring a cable-barrier to a support surface characterised by the steps of:
a) connecting one end of at least one anchor-cable to an anchor-body on a
terminal post of the cable-barrier;
b) anchoring the other end of the anchor-cable(s) to the support surface,
wherein said anchor-body is adapted to, in use:
- receive and retain one or more anchor-cables which are anchored
so as to
counter balance the force applied to the terminal post by said barrier-
cable(s);
and
- release said anchor-cables, during a collision with a vehicle, in
situations
where said anchor-cables are capable of acting as a ramp and/or snag during
said collision.
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The anchor-cable(s) may be anchored to the support surface in a variety of
different
ways.
In general, the anchor-cable(s) may be anchored to the support surface in a
manner
which reduces any substantially upward force exerted by the anchor-cable at
the anchor
point(s).
In preferred embodiments, the anchor-cable(s) may be attached to:
- a strut running substantially parallel to the support surface, and which may
be
connected to the ground; and
- at least two points along a strut, such that at least some of any
substantially
upward force can be converted to a sheer force which is substantially parallel
to the longitudinal axis of the strut.
Preferably, the anchor-cables may be connected at two or more points along the
strut.
Preferably, the strut prevents the mid-point of the anchor-cables from lifting
away from
the ground upon application of a force.
Thus, it should be appreciated that preferred embodiments of the present
invention may
have a number of advantages over the prior art which can include:
- providing a terminal post for, and/or method of anchoring, a cable-barrier
which
can release anchor-cable downwardly extending from the terminal post of a
cable-
barrier, in situations where said anchor-cables are capable of acting as a
ramp
and/or snag during a collision;
- a barrier-cable release mechanism on a terminal post of a cable-barrier
which
releases barrier-cables when a vehicle collides with the terminal post and/or
anchor-cables of the cable-barrier;
- A barrier-cable release mechanism that can withstand impact from
collisions from
both directions.
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BRIEF DESCRIPTION OF DRAWINGS
Further aspects of the present invention will become apparent from the
following
description which is given by way of example only and with reference to the
accompanying drawings in which:
Figure 1 shows a partial side elevation view of a cable-barrier in
accordance with
the preferred embodiment of the present invention;
Figure 2 shows further views of a cable-barrier, where;
Figure 2a shows a further partial side elevation view and
corresponding plan
elevation view of a cable-barrier in accordance with the preferred
embodiment of the present invention;
Figure 2b shows a corresponding plan elevation view of the cable-
barrier as
shown in Figure 2a;
Figure 3 shows a further perspective elevation view of a cable-barrier
in accordance
with the preferred embodiment of the present invention;
Figure 4 shows a perspective elevation view of the top of the terminal
post shown in
Figure 1 without any cables attached thereto;
Figure 5 shows a perspective elevation view of the top portion of the
terminal post
(as indicated by Box A in Figure 3) with cables and anchor-cables attached
thereto;
Figure 6 shows a photograph of the terminal post of the present
invention with
cables and anchor-cables attached thereto;
Figure 7 shows a front elevation view of the anchor-body washer; and
Figure 8 shows a detail view of the distal end of the ground strut
connection, as
indicated by box B in Figure 3.
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BEST MODES FOR CARRYING OUT THE INVENTION
Figures 1 to 3 show a cable-barrier (1). The cable-barrier (1) includes a
plurality of posts
(2) (of which only one is shown) which support the cables (3) of the cable
barrier (1). The
posts (2) are secured to the ground (4) via concrete footings (5). The cable-
barrier (1)
also includes a terminal post (6) which is also secured to the ground (4) via
a concrete
footing (5). The terminal post (6) is at an angle of approximately 8 degrees
to the
vertical, as indicated by double ended arrow X. The terminal post (6) is
further secured
to the ground (4) via two anchor-cables (7) which are connected to the ground
(4) via a
strut (8) which runs parallel to the surface of the ground (4) and is attached
thereto via
bolts (indicated by arrow 21 on Figure 2 only) which are connected to
threadable socket
portions (indicated by arrow 22 on Figure 2 only) of reinforcing elements
(100) embedded
in the concrete footings (5). As shown in Figures 1 to 3, the anchor-cables
(7) travel
through the hollow centre of the strut (8) from an entry point (9) to the
terminal end of the
strut (10) where the anchor-cables (7) are secured by a bolt (39) and washer
(40)
arrangement (as indicated by arrow B, and Box B in Figures 2 and 3
respectively). The
bolt and washer arrangement is shown in detail in Figure 8.
The terminal post and anchor body arrangement, of the cable-barrier, as
specifically
indicated by Box A on Figure 3, is shown in greater detail in Figures 4 to 6.
The terminal post (6) has a substantially upright portion (11) and a post
transition plate
(12) which is welded on top of upright portion (11). Additionally, two
vertical strain plates
(13) are welded to the post transition plate (12). The strain plates (13) form
a cable-
portion in the form of a slot (14).
Also shown in Figures 4 to 6 is an anchor-body (15). The anchor-body (15) has
two side
plates (16) which are respectively attached to the outside of the two vertical
strain plates
(13). The two side plates (16) are connected to one another via two top plates
(17) which
are also respectively welded (indicated by line 18). At the distal end of the
side plates
(16) two further plates (19) are welded together, which form an aperture (20).
Figure 5 show the terminal post (6) and anchor-body (15) in an in use
position, within a
cable-barrier system. As shown, the terminal ends of cables (3) include a
threaded
section (30) which passes through the slot (14) of the cable-portion. To
retain the cables
within the threaded section (30), the cables (3) are secured within slot (14)
via nuts and
CA 02913772 2015-12-02
bolts (31) and a washer (32). Additionally, the anchor-cables (7) are retained
within a
threaded section (34) which passes through aperture (20) in the anchor-body.
Similarly,
the anchor-cables (7) are retained therein via a washer (37) and nuts (41).
Figure 6 shows a photograph of both the terminal post (6) and anchor-body (15)
while in
use.
Figure 7 shows the washer for the anchor-cables (7) in greater detail. As
indicated, the
washer (37) has two apertures (38) through which the threaded sections of the
anchor-
cables (7) can pass through and be retained in.
In use, if a vehicle travelling in direction Y hits or contacts the anchor-
cables (7) the
resultant force from the impact moves the anchor-cables (7) substantially in
the direction
of arrow (200) which releases the anchor-cables (7) from the anchor-body (15).
As the cables (3) of the cable-barrier (1) are held under tension in the
direction of arrow
(600) the release of the anchor-cables (7) causes the terminal post (6) to
deform
substantially in the direction of arrow (601) and as a consequence the cables
(3) move in
a substantially vertical direction as indicated by arrow (800) and are
released from slot
(14) of the cable portion.
A similar net result occurs if a vehicle impacts into the terminal post (6)
itself as any
substantial deformation of the terminal post (6) causes the respective release
of the
cables (3) and/or anchor-cables (7) from the slot (14) of the cable-portion of
the terminal
post or the aperture (20) of the anchor-body (15). This is the outcome of when
a vehicle
impacts the anchor-cables (7), the terminal post (6) or anchor-body (15)
substantially
side-on. Here, the force causes the terminal post (6) and anchor-body (15) to
twist or
buckle, due to the opposing forces between the cable tension and direction of
force
caused by the impact.
Aspects of the present invention have been described by way of example only
and it
should be appreciated that modifications and additions may be made thereto
without
departing from the scope thereof as defined in the appended claims.
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